Heat exchanger with reinforcing plate

ABSTRACT

The present invention relates to a heat exchanger ( 1 ) comprising:
         a tube bundle ( 2 ) comprising a plurality of tubes ( 2 ) placed parallel to one another, said tube bundle ( 2 ) comprising fins ( 6 ) placed between the tubes ( 2 );   two collectors ( 3 ), one collector ( 3 ) being placed on both sides of the tube bundle ( 2 ), each collector ( 3 ) comprising a collector plate ( 4 ), said collector plate ( 4 ) comprising orifices inside which the ends of the tubes ( 2 ) are introduced, and a rim ( 41 ) forming a groove ( 42 ) which is designed to receive a cover ( 8 ); and   at least one reinforcement plate ( 10 ) placed between a collector plate ( 4 ) and the fins ( 6 ), parallel to the collector plate ( 4 ) and brazed against at least part of the tubes ( 2 ) of the tube bundle ( 2 ) and said collector plate ( 4 ),
 
the at least one reinforcement plate ( 10 ) comprising a lateral wall ( 101 ) which projects in the direction of the collector plate ( 4 ), and covers the rim ( 41 ) of the collector plate ( 4 ) at least partially, said lateral wall ( 101 ) being brazed against said rim ( 41 ) of the collector plate ( 4 ) in order to secure the reinforcement plate ( 10 ) on the collector plate ( 4 ).

The invention relates to a heat exchanger, in particular for a motor vehicle.

More particularly, it relates to a heat exchanger of the type comprising a plurality of tubes between which fins are inserted. The tubes are generally tubes with a circular, oval or oblong cross-section, defined by a large axis and a small axis, and having ends which are introduced into orifices in a collector plate. Reference is made to a brazed heat exchanger when the connection between the tubes and the collector plate is carried out by brazing. This connection is thus rigid, and cannot compensate for the phenomena of expansion and retraction associated with the variations of temperature during the use of the heat exchanger. Over a period of time, as a result of these thermal expansions and contractions, the metal of which the tubes and the collector plate are made can become fatigued, and this can give rise to the formation of cracks at the connection between the tubes and the collector plate, and thus potentially generate leakages or ruptures.

A known solution consists of placing one or a plurality of flat reinforcement plates between the collector plate and the fins. These flat reinforcement plates are generally brazed with the collector plate and the tubes, in order to increase the resistance of the assembly to the forces associated with the thermal expansion and retraction. However, flat reinforcement plates of this type may not be sufficient to reduce the risks of rupture or formation of cracks.

One of the objectives of the present invention is thus to eliminate at least partially the disadvantages of the prior art, and to propose an improved heat exchanger.

The present invention thus relates to a heat exchanger comprising:

-   -   a tube bundle comprising a plurality of tubes placed parallel to         one another, said tube bundle comprising fins placed between the         tubes;     -   two collectors, one collector being placed on both sides of the         tube bundle, each collector comprising a collector plate, said         collector plate comprising orifices inside which the ends of the         tubes are introduced, and a rim forming a groove which is         designed to receive a cover; and     -   at least one reinforcement plate placed between a collector         plate and the fins, parallel to the collector plate and brazed         against at least part of the tubes of the tube bundle and said         collector plate,     -   the at least one reinforcement plate comprising a lateral wall         which projects in the direction of the collector plate, and         covers the rim of the collector plate at least partially, said         lateral wall being brazed against said rim of the collector         plate.

The presence of the lateral wall reinforces all the more the connection between the tubes and the collector plate, and makes it possible to reduce the risks of rupture or formation of cracks as a result of the variations of heat, but also as a result of the vibrations and pressure of the first liquid coolant within the heat exchanger.

According to an aspect of the invention, the reinforcement plate comprises two parallel tongues and at least one base connecting the two tongues at one of their ends, such as to form a space for receipt of the tubes, the tongues being in contact with the edge of the tubes.

According to another aspect of the invention, the tongues of the reinforcement plate comprise notches which are complementary with the edge of the tubes.

According to another aspect of the invention, the space for receipt of the tubes comprises braces which pass between two tubes, and connect the tongues of the reinforcement plate.

According to another aspect of the invention, the braces of the space for receipt of the tubes fill the space between two tubes, and are brazed with said tubes.

According to another aspect of the invention, at one collector at least, the heat exchanger comprises two reinforcement plates which are placed opposite one another, each on a lateral side of the heat exchanger.

As an alternative, according to another aspect of the invention, at one collector at least, the heat exchanger comprises a single reinforcement plate, the lateral wall of which is brazed with the rim of the collector plate around the entire periphery of said collector plate.

According to another aspect of the invention, the reinforcement plate comprises a skirt around at least part of the periphery of the space for receipt of the tubes, said skirt projecting in the direction of the fins.

According to another aspect of the invention, the skirt has a height corresponding to at least the distance between the reinforcement plate and the fins.

According to another aspect of the invention, the lateral wall of the reinforcement plate comprises crimping lugs.

Other characteristics and advantages of the invention will become more apparent from reading the following description, provided by way of non-limiting illustration, and from the appended drawings in which:

FIG. 1 shows a schematic representation of a heat exchanger;

FIG. 2 shows a schematic representation in a view from the front of a collector of a heat exchanger;

FIG. 3 shows a schematic representation in transverse cross-section of a collector of a heat exchanger;

FIG. 4 shows a partial schematic representation in perspective in a view from above of a collector of a heat exchanger;

FIG. 5 shows a partial schematic representation in a view from above of the reinforcement plate of a collector according to a first embodiment;

FIG. 6 shows a partial schematic representation in a view from above of the reinforcement plate of a collector according to a second embodiment;

FIG. 7 shows a partial schematic representation in a view from above of the reinforcement plate of a collector according to a third embodiment;

FIG. 8 shows a partial schematic representation in perspective in a view from below of the collector in FIG. 4 according to a first variant;

FIG. 9 shows a partial schematic representation in perspective in a view from below of the collector in FIG. 4 according to a second variant;

FIG. 10 shows a partial schematic representation in perspective in a view from above of a collector of a heat exchanger according to another embodiment.

Elements which are identical in the different figures bear the same references.

The following embodiments are examples. Although the description relates to one or a plurality of embodiments, this does not necessarily mean that each reference concerns the same embodiment, or that the characteristics apply only to a single embodiment. Single characteristics of different embodiments can also be combined or interchanged in order to provide other embodiments.

In the present description, certain elements or parameters can be indexed, such as, for example, the first element or second element, as well as the first parameter and second parameter, or also the first criterion and second criterion, etc. In this case, simple indexing is involved in order to differentiate and designate elements or parameters or criteria which are similar but not identical. This indexing does not imply priority of one element, parameter or criterion over another, and it is easily possible to interchange these designations without departing from the context of the present description. Nor does this indexing imply an order in time, for example in order to evaluate certain criteria.

FIG. 1 shows a heat exchanger 1 with a generally parallelepiped form, comprising a bundle forming a plurality of tubes 2, inside which a first liquid coolant can circulate. The tubes 2 can have a cross-section which is circular, or preferably a cross-section which is oval or oblong, designed by a large axis and a small axis, and the tubes are placed parallel to one another. Between the tubes 2 there are placed fins 6 which act as pertubators, and increase the surface area of heat exchange with a second liquid coolant passing between the tubes 2.

The tubes 2 and the fins 6 are generally made of metal. The tubes 2 and the fins 6 forming the bundle are secured to one another by brazing. The fins 6 are for example undulating or crenellated strips which are placed between the tubes 2 and secured to said tubes 2 by brazing. Reference is then made to a brazed bundle.

The heat exchanger 1 also comprises two collectors 3 (also known as water tanks), a collector 3 being placed at each end of the tubes 2. These collectors 3 each comprise a collector plate 4 and a cover 8 which covers the collector plate 4 and closes the collector 3. These collectors 3 permit the collection and/or distribution of the first liquid coolant, so that it circulates in the tubes 2.

The collector plate 4 forms the sealed connection between the collector 3 and the tube bundle 2. The collector plate 4 can be made of metal. In addition, the collector plate 4 can have a generally rectangular form. The collector plate 4 also comprises a plurality of orifices, which have a form corresponding to the form of the cross-section of the tubes 2, and can receive the ends of the tubes 2. The tubes 2 are secured to the collector plate 4 in a sealed manner by brazing.

As shown in FIG. 2, the heat exchanger 1 also comprises, at one of its collectors 3 at least, at least one reinforcement plate 10 which is placed between the collector plate 4 and the fins 6. This reinforcement plate 10 is positioned parallel to the collector plate 4, and is brazed against at least part of the tubes 2 of the tube bundle 2 and against said collector plate 4. The reinforcement plate 10 makes it possible to reinforce both the collector plate 4 and the ends of the tubes 2, and thus makes it possible to reduce the risks of formation of cracks as a result of the fatigue of the metal during the service life of the heat exchanger 1.

Preferably, each collector 3 comprises at least one reinforcement plate 10, however it is perfectly possible to conceive of a heat exchanger 1 wherein a single one of the collectors 3 comprises at least one reinforcement plate 10.

In the embodiment illustrated in FIG. 2, at one of its collectors 3 at least, the heat exchanger 1 comprises two reinforcement plates 10. These reinforcement plates 10 are placed opposite one another, each on a lateral side of the heat exchanger 1.

In this case, the lateral side of the heat exchanger 1 means the sides of the heat exchanger 1 which do not bear a collector 3, and are situated on both sides of the frontal and rear faces of the heat exchanger 1 by means of which the second liquid coolant passes through said heat exchanger 1. The frontal face is the face by means of which the second liquid coolant enters, and the rear face is the face by means of which said second liquid coolant exits.

It is nevertheless perfectly possible to conceive of an embodiment (not represented) in which the exchanger 1 comprises a single reinforcement plate 10 at one of its collectors 3 at least. This single reinforcement plate 10 has a surface area which is at least equal to that of the collector plate, and its lateral wall 101 is brazed with the rim 41 of said collector plate 4 around the entire periphery of the collector plate 4.

Since the tubes 2, the fins 6, as well as the collector plates 4 and the reinforcement plates 10 are brazed, the latter are made of a metal material, in particular of aluminum or aluminum alloy.

As illustrated in FIG. 3, which is a schematic representation of a transverse cross-section of a collector 3, the collector plate 4 comprises around its entire periphery a rim 41 which rises towards the cover 8, such as to form a groove 42 in which the cover 8 is inserted. A seal (not represented) is inserted in this groove 42, in order to ensure the sealing between the cover 8 and the collector plate 4. The cover 8 is retained against the collector plate 4 by crimping lugs 43 which are placed on the rim 41 and are folded back on a shoulder of the cover 8.

The reinforcement plate 10 comprises in particular a lateral wall 101 which projects in the direction of the collector plate 4, and covers the rim 41 of the collector plate 4 at least partially. This lateral wall 101 is brazed against said rim 41 of the collector plate 4. The presence of the lateral wall 101 reinforces all the more the connection between the tubes 2 and the collector plate 4, and makes it possible to reduce the risks of rupture or formation of cracks as a result of the thermal variations, but also as a result of the variations and pressure of the first liquid coolant within the heat exchanger 1.

In order to maximize the reinforcement and the brazing between the reinforcement plate 10 and the collector plate 4, the lateral wall 101 covers the rim 41 over its entire height, in particular as far as the start of the crimping lugs 43. In addition, the reinforcement plate 10 can be brazed with the face of the collector plate which faces the fins 6, more particularly at the groove 42.

FIG. 4 shows a partial schematic representation in perspective of the collector 3 of the heat exchanger 1. In this FIG. 4, the lateral wall 101 of the reinforcement plate 10 covers the rim 41 of the collector plate 4 continuously, i.e. around the entire periphery of the reinforcement plate 10.

As illustrated in FIG. 4, the collector plate 4 can also comprise on the lateral sides of the heat exchanger 1 a lateral rebate 44 which is folded back in the direction of the tube bundle 2, such as to retain a lateral cheek 12, used in particular to secure the heat exchanger 1 in its location in the motor vehicle.

FIG. 5 shows a reinforcement plate 10 in greater detail. The reinforcement plate 10 comprises in particular two parallel tongues 10 a, 10 b, and at least one base 10 c which connects the two tongues 10 a, 10 b at one of their ends. These tongues 10 a, 10 b, as well as the base(s) 10 c, are placed in particular on a plane parallel to that of the collector plate 4. The tongues 10 a and 10 b are placed respectively against the frontal and rear faces of the heat exchanger 1, and the base 10 c is placed against a lateral side of said heat exchanger 1. The tongues 10 a, 10 b and the at least one base 10 c form a space 103 for receipt of the tubes 2 in the center of the reinforcement plate 10. At this receipt space 103, the tongues 10 a, 10 b are in contact with the edge of the tubes 2.

In order to improve the brazing and the assembly, the tongues 10 a, 10 b of the reinforcement plate 10 can comprise notches 105 which are complementary with the edge of the tubes 2.

When, at one of its collectors 3 at least, the heat exchanger 1 comprises two reinforcement plates 10, said reinforcement plates 10 comprise only a single base 10 c, and have a general form of a “U” on a plane parallel to that of the collector plate 4. When, at one of its collectors 3 at least, the heat exchanger 1 comprises a single reinforcement plate 10, said reinforcement plates 10 comprise two bases 10 c, and have a general form of a parallelepiped, with the receipt space 103 in the center.

In order to obtain good strength, the reinforcement plate 10 is formed in a single piece, for example by stamping, and the lateral wall 101 is integral with said reinforcement plate 10, and in particular with the tongues 10 a, 10 b and the base 10 c.

According to a particular embodiment illustrated in FIGS. 6 and 7, the receipt space 103 of the tubes 2 comprises braces 104 passing between two tubes 2 and connecting the tongues 10 a, 10 b of the reinforcement plate 10. As shown in FIG. 6, these braces 104 need not be in contact with the tubes 2, in order to limit the increase in the mass of the heat exchanger 1 as a result of the presence of the reinforcement plate 10.

According to a variant illustrated in FIG. 7, the braces 104 of the receipt space 103 fill the space between two tubes 2, and are brazed with said tubes 2. This variant makes it possible in particular to increase the surface area of brazing between the reinforcement plate 10 and the tubes 2, and thus to reinforce them even further.

As shown in FIGS. 8 and 9, the reinforcement plate 10 can also comprise a skirt 102 around at least part of the periphery of the space 103 for receipt of the tubes 2. This skirt 102 projects in the direction of the fins 6 of the tube bundle 2.

This skirt 102 makes it possible in particular to increase further the surface area of brazing between the reinforcement plate 10 and the tubes 2, and thus to reinforce them even further. In addition, this skirt 102 makes it possible to limit the circulation of the second liquid coolant in the space between the fins 6 and the collector 3, and thus to improve the performance of the heat exchanger 1, by forcing the second liquid coolant to circulate in the fins 6, where the surface area of exchange is greatest. For this purpose, the skirt 102 preferably has a height which corresponds at least to the distance between the reinforcement plate 10 and the fins 6.

As shown in FIG. 8, the skirt 102 can be present only on part of the periphery of the receipt space 103, more particularly only at the tongues 10 a, 10 b. The skirt 102 can also be present around the entire periphery of the receipt space 103, and thus be present both at the tongues 10 a, 10 b, and the base(s) 10 c, as illustrated in FIG. 3.

FIG. 10 shows an embodiment of the reinforcement plate 10 wherein the lateral wall 101 additionally comprises crimping lugs 106. These lugs 106 for crimping of the reinforcement plate 10 are placed between the lugs 43 for crimping of the collector plate 4, and reinforce the retention of the cover 8 against the collector plate 4.

Thus, it can be seen clearly that the heat exchanger 1 according to the invention makes possible improved strength of the collector plate 4 and of the tubes 2, as a result of the presence of the reinforcement plate 10 and its lateral wall 101. 

1. A heat exchanger comprising: a tube bundle comprising a plurality of tubes placed parallel to one another, and fins placed between the tubes; two collectors, one collector being placed on both sides of the tube bundle, each collector comprising a collector plate, said collector plate comprising orifices inside which the ends of the tubes are introduced, and a rim forming a groove configured to receive a cover; and at least one reinforcement plate placed between one of the collector plates and the fins, parallel to the collector plate and brazed against at least part of the tubes of the tube bundle and said collector plate, wherein the at least one reinforcement plate comprises a lateral wall which projects in the direction of the collector plate, and covers the rim of the collector plate at least partially, said lateral wall being brazed against said rim of the collector plate in order to secure the reinforcement plate on the collector plate.
 2. The heat exchanger as claimed in claim 1, wherein the reinforcement plate comprises two parallel tongues and at least one base connecting the two tongues at one of their ends, such as to form a space for receipt of the tubes, the tongues being in contact with the edge of the tubes.
 3. The heat exchanger as claimed in claim 2, wherein the tongues of the reinforcement plate comprise notches which are complementary with the edge of the tubes.
 4. The heat exchanger as claimed in claim 2, wherein the space for receipt of the tubes comprises braces which pass between two tubes, and connect the tongues of the reinforcement plate.
 5. The heat exchanger as claimed in claim 4, wherein the braces of the space for receipt of the tubes fill the space between two tubes, and are brazed with said tubes.
 6. The heat exchanger as claimed in claim 1, comprising, at one collector at least, two reinforcement plates which are placed opposite one another, each on a lateral side of the heat exchanger.
 7. The heat exchanger as claimed in claim 1, comprising, at one collector at least, a single reinforcement plate, the lateral wall of which is brazed with the rim of the collector plate around the entire periphery of said collector plate.
 8. The heat exchanger as claimed in claim 2, wherein the reinforcement plate comprises a skirt around at least part of the periphery of the space for receipt of the tubes, said skirt projecting in the direction of the fins.
 9. The heat exchanger as claimed in claim 8, wherein the skirt has a height corresponding to at least the distance between the reinforcement plate and the fins.
 10. The heat exchanger as claimed in claim 1, wherein the lateral wall of the reinforcement plate additionally comprises crimping lugs. 